The Prince's reign was marked by excessive and highly inventive taxing, motivated by the increasing debt and his ambition to accumulate a sizable personal fortune on the side. Iancu was to go down in history as the mind behind the much-hated văcărit tax, whereby every tenth head of cattle was confiscated by the state (vacă is Romanian for "cow").

Brutti became part of the retinue and was placed in charge of finances. His privileged position angered Chiajna, and she took to undermining Iancu's standing, forming an alliance with disgruntled boyars. What added to Iancu's isolation were his privileged contacts with the Holy Roman Empire, presumably entertained in order to offer a safe haven in case of need. When he received news of the Porte's intent to depose him, Iancu fled the country, carrying an immense fortune that was said to fit in 100 carts (of which 40 would have been filled with currency alone). He attempted to take refuge on newly-bought estates in Transylvania, but he was arrested on his passage through Poland and decapitated in Lviv.

Iancu Sasul fathered a son, Bogdan Sasul (mentioned in 1596), and a daughter, Chrisotina (married to a certain Antonios Katakalos).